This invention relates to a method of, and an apparatus for, controlling the dispensing of money in the form of units having a plurality of denominations. The invention is particularly, but not exclusively, applicable to machines such as vending machines which receive coins of a plurality of denominations, and which have a plurality of stores each containing coins of a respective denomination, and each possibly being capable of being replenished by insertion of coins into the vending machine. Means are provided for dispensing coins from the stores in an amount which corresponds to the difference between the amount inserted, and the value of the vend or vends performed by the machine.
The invention is not limited to such arrangements. The dispensed monetary units could be, for example, banknotes, or a mixture of banknotes and coins. The invention also has wider applicability than vending machines; it may be applied to change-giving machines of any type.
In the field of vending machines, it is well know to use a dispensing control means which calculates a preferred combination of coins for dispensing in the form of change. One typical way of achieving this, referred to as the xe2x80x9cleast number of coinsxe2x80x9d method, involves using as many higher-denomination coins as possible, so that the total number of dispensed coins is minimised. This is intended to maximise the number of coins retained in the stores so that change remains available for the maximum number of transactions. Also, users of machines generally prefer their change in the form of fewer high-denomination coins.
EP 0 653 085 A (the contents of which are incorporated herein by reference) discloses a method of determining the combination of monetary units to be dispensed in which several combinations of monetary units totalling the desired amount are calculated.
In such systems, there is often a tendency for the apparatus frequently to dispense the same denomination. For example, in machines that have many products that can be vended at a vend price of 40p, users will often insert 50p or £1 coins. Assuming that the machine can dispense a variety of different coin denominations, the xe2x80x9cleast number of coinsxe2x80x9d technique may result in the apparatus frequently selecting 10p, or a combination of a 50p and 10p, for dispensing as change. This reduces the number of available 50p and 10p coins for future change-giving operations. If for example the machine runs out of 10p coins, it may no longer be possible to give change, or perhaps only possible by using a large number of smaller-denomination coins which is less desirable from the point of view of the machine user.
As a machine is used, the relative numbers of coins (or other units) of different denominations which are available for dispensing tends to vary, depending upon the types of units inserted, and the vend prices.
WO 95/14290 (the contents of which are incorporated herein by reference) discloses a method similar to that of EP 0 653 085 A but in which an availability factor, dependent on the number of available units of at least one denomination, is also used to determine the best distribution of units for dispensing.
The method described in that document represents one technique for compensating at least partly for this change in distribution, so as to maintain as many different denominations available for as long as possible. The present invention can be used as an alternative technique for maintaining as many different denominations available for as long as possible.
The present invention provides a method of controlling the dispensing of money in the form of units available in a plurality of denominations comprising selecting the units for a dispensing operation by considering the change in the number of stored units for each denomination over at least two preceding dispensing operations.
The invention also provides an apparatus for dispensing money in the form of units available in a plurality of denominations comprising means for selecting the units for a dispensing operation by considering the change in the number of stored units for each denomination over at least two preceding dispensing operations.